Stumped and Frustrated with a Holley 670 Hesitation

inertia said

Is this from a standing start,, or from speed..??

Initial timing??

The secondary springs are color coded, and there's about 7 diff strengths,, which do you have..?? By the sound of it, you need a stiffer spring.. or you may need to change accel pump cams to a longer stroke..

White - Lightest
Yellow (Short Spring)
Yellow
Purple
Plain (Steel grey)
Brown
Black - Heaviest

hope it helps.

Click to expand...

From either a standing or rolling its the exact same.

I have 20* initial and 35 total timing.

I have 3 springs, Yellow, Plain, Black. I've tried all 3 with the 1" spacer and there was no difference. With the 5/16" spacer Im currently trying the plain. Figure I would start over since I changed spacers.

I have seen the accelerator pump squirt into the primary side when just standing over the carb so I know that is working, but the pump shot may need to be changed like you mentioned. Someone awhile back mention the air bleeds may be plugged. Is this a possibility?